Question

9) Look up the Rosemount 3051 Pressure Transmitter. a) What is the difference between the Differential Pressure and Absolute Pressure measurement? b) What is the difference between Gage and Absolute pressure? c) What is the difference between the Coplanar Pressure Transmitter and the In-Line Pressure Transmitter? d) What is meant by HART Communication protocol. e) Is this transmitter approved for use with drinking water? Aboard ships? In China as intrinsically safe. f) Name all the transmitter output options.

Answer 1

Rosemount 3051 is in line pressure transmitter, industry standard for guage and absolute pressure measurement.

a) in absolute pressure, reference is guage pressure of media plus atmospheric pressure, due to elevation change reference point also change due to atmospheric pressure differences. But differerential pressure sensor measure difference between media pressure and atmosphere pressure, true differerential pressure sensor used to identify difference between two separate physical areas.

b) Gauge pressure sensor uses reference to atmosphere around the sensor, there is pressure change due to sensing element deflection, a reference point is needed what pressure is exactly being measured. But in absolute pressure, reference is gauge media plus atmospheric pressure, due to elevation change reference point also change due to differences between atmosphere differences.

c) Coplanar pressure transmitter has two process connection on the bottom side of the transmitter and we can easily connect it to differerential pressure sensor, but it can also be used with guage and absolute pressure. Inline pressure transmitter configuration is designed for accurate and true gauge and absolute pressure measurement, it uses pizoresistive sensor which converts resistance into electrical signal.

d) HART(Highway Addressable Remote Transducer) is combination of analogue and digital industrial protocol, it is advantageous that it can communicate 4-20mA anlalouge instruments current loop. It communicates in multi drop and point to point.

e) yes is approved for drinking water and can also be used for aboard ships.